Magnetic pole structure



Nov. 13, 1956 R. M. HEINTZ 2,770,744

MAGNETIC POLE STRUCTURE Filed April 20, 1953 3 Sheets-Sheet 1 [NVEVTOR AYTOR/VBS Nov. 13, 1956 R. M. HEINIV'Z 2,770,744

MAGNETIC POLE STRUCTURE Filed April 20, 1953 3 Sheets-Sheet 2 is! By .Hazb? AWE/VHF Nov. 13, 1956 R. M. HEINTZ 2,770,744

MAGNETIC POLE STRUCTURE Filed April 20, 1953 s Sheets-Sheet 3 United States Patent MAGNETIC POLE STRUCTURE Ralph M. Heintz, Los Gatos, Calif, assignor to Jack &

Heintz, Inc., Cleveland, Ohio, a corporation of Delaware Application April 20, 1953, Serial No. 349,633

8 Claims. (Cl. 310-218) The present invention relates to pole structure suitable for employment in most types of dynamo-electric machinery. For example, the pole structure admits of use in the machine described in my copending application for Letters Patent of the United States, Serial No. 349,634, now Pat. 2,706,260, entitled Liquid Cooled Dynamo-Electric Machine and filed concurrently herewith.

Among the objects of this invention are the following: to provide compact pole piece structures; to provide, as units, pole piece structures admitting of ready and convenient attachment to the yoke of a dynamoelectric machine; and to provide a laminated pole structure suitably encased to permit liquid coolant to serve as a heat receiving medium therefore without interfering with the necessary electric characteristics.

The pole structure per se comprises a plurality of similar laminations each preferably having at least one arcuate edge. The laminations are assembled in stacked array with the arcuate edges similarly oriented to define a common arcuate surface. Notches are preferably formed in the lamination edges opposed to the arcuate edges to form lateral troughs when the laminations are stacked in close array, such troughs accommodating welds to secure the laminations in the array formation. A retaining cup is provided to encase the laminations such that the arcuate surface formed thereby is exposed through the mouth of the cup.

The laminations are suitably secured within the cup. One convenient means for providing the attachment also contemplates structure for securing the cup and laminations to the yoke of a machine, with the exposed arcuate surface directed inwardly thereof in the direction of the rotor. With the laminations inserted in the cup, which preferably tightly encases the array, apertures or holes are bored through the cup and part way into the lamination array through one or more of the trough welds, such apertures opening in the surfaces of the cup and lamination array apposed to the formed arcuate surface. Internally threaded thimbles of a length slightly less than that of the aperture depth are formed in each aperture to unite the lamination array and cup. Suitable apertures in the yoke accommodate cooperating screws adapted to be threaded into the thimbles to secure the pole piece structure as outlined to the yoke.

As was mentioned, pole piece units in accordance with the present invention may be applied to most known types of dynamo-electric machines. The present invention will be explained in connection with its incorporation in, for example, a D. C. generator as outlined in the above referenced application. Such a machine admitting of circulating liquid coolant employs an outer shell of tubular configuration comprised of, for example, steel tubing. An inner shell of stainless steel tubing or the like is preferably axially alined with the outer shell and secured thereto by annular closures or radial supports. An annular yoke is provided for the machine which fits within the annular space between the inner 2,770,744 Patented Nov. 13, 1956 and outer shells in juxtaposition with the outer shell and of a cross-sectional dimension sufficiently less than the radial dimension of the annular space between the shells as to accommodate main poles, interpoles, and windings therefor.

The annular yoke is peripherally slotted along planes perpendicular to the axis of the machine, the slotting being accomplished conveniently through the use of circular milling cutters. The slots thus formed penetrate through the yoke midway between the positions where the main poles and interpoles are to be secured, thereby leaving bridges at these positions connecting the rings formed by the slotting. The points of the bridges are removed to provide truncated supports adapted to accomodate studs or bolts which fasten t0 the thimbles located in the pole structures. Grooves are provided in the periphery of the yoke extending in directions parallel to the machine axis and preferably disposed approximately apart around the circumference of the yoke. Adjacent grooves are respectively open and closed at opposite ends to provide tortuous paths for the liquid coolant which is adapted to be impelled through the machine by, for example, built-in turbo-type pumps employing helicoidal vanes. For the purpose of the present invention, it will suffice to know that the path of the coolant is axially of the machine along two of the yoke troughs and circumferentially of the machine along the slots to return axially of the machine along the other yoke grooves.

The inner shell of the machine is suitably apertured to accommodate the arcuate surface of each pole piece formed by the similarly oriented edges of the laminations. The retaining cup for the laminations is preferably provided with a peripheral flange about the mouth thereof adapted to bear along the outer circumference of the inner shell to aid in the support of the pole structure from the yoke and also to prevent coolant from entering the air gap between the rotor and stator construction. Thus, it may be appreciated that while this invention per se is directed to magnetic pole pieces, in the particular situation herein referred to, a certain degree of cooperation is extended to the invention by the yoke and inner shell of the machine which it is adapted to serve.

Further, if it is desired to employ compensating windings on a machine equipped with pole pieces in accordance with the present invention, this is conveniently arranged by providing a pair of slots extended through the lamination array (in a direction axially of the machine when the pole piece is assembled therewith) and cooperating slots in the retaining cups for the laminations to accommodate such compensating windings.

Other features, objects and aims of the present invention will become more apparent to those skilled in the art from the following detailed description thereof when viewed in the light of the accompanying drawings wherein:

Fig. 1 shows in end elevation one suitable type of yoke adapted for cooperation with the pole piece structure of the present invention;

Fig. 2 is a view in side elevation of the yoke represented in Fig. 1;

Fig. 3 is a fragmentary vertical sectional view of a machine equipped with structure in accordance with the present invention, the plane of section being taken transversely of the longitudinal axis of the machine;

Fig. 4 shows in developed section the structure of Fig. 3, the plane of section being taken along the line 4-4 and developed along the center line as indicated;

Fig. 5 is a detailed representation in side elevation of a single lamination adapted to be employed in the pole structure of the present invention.

Fig. 6 shows in plan a suitable retaining cup for the laminations in accordance with Fig. and,

Fig. 7 is a cross sectional view of the cup of Fig. 6, the plane of section being indicated by the line 7--'7 shown in Fig. 6.

Referring now to the drawing-and; particularly to Figs. 1 and 2, there is shown an annular yoke 11 of high permeability soft iron or steel such as that manufactured under the trade name Armco Ingot-lron. As is shown best in Fig. 2, slots 13- are' formed by circular milling cutters in the periphery of the yoke; occupying parallel planes perpendicular to the axis 15 of the yoke or ma chine and leaving peripheral rings 17 joined together by bridges 19 and 19', the points of the bridges having been removed to provide the. truncated appearance illustrated.

In order to provide for coolant circulation, longitudinal grooves or troughs 21 are formed. in the external periphery of the yoke 11, adjacent grooves or troughs 21 being open at opposed ends and closed at the other respective opposed ends to force the coolant to traverse the yoke longitudinally along one trough and'then circumferentially to the adjacent groove for return. The remaining grooves or troughs similarly cooperate in the circulatory system to provide for heat transfer from the stator structure to the coolant. Also, as is shown in- Fig. 2;, the. periphery of the yoke 11 is penetrated by drilling or boring to form the apertures 23 and 25in the bridges 19 and 19 respectively to accommodate attaching means for stator structure later to be described.

Referring now to Figs. 3 and 4 it may be seen that the yoke 11 is adapted to fit snugly. within an outer tubular shell 31 preferably comprised of steel, tubing. An inner tubular shell 33 of non-magnetic material, as for example, stainless steel tubing, is supported within the annular yoke 11 from the outer shell 31 by means of suitable radial or bracket supports 35, the internal diameter of annular yoke 11 being sufficiently greater than the external diameter of the tubular shell 33 as to provide an annular space therebetween to accommodate thefield structure.

Commutating interpoles generally indicated at 41 are of solid construction, each comprising a substantially rectangular slug 43 having an outer flange 45 to bear against the inner surface of inner shell 33, the slug 43 being passed through an aperture in the inner shell 33. The slugs 43 are suitably bored and tapped to accommodate bolts 47 which secure them to the yoke 11.. Suitable windings 51 (Fig. 4). are disposed about the slugs 43 between the inner shell 33 and the yoke 11. As the invention is not concerned. with the particular typev rotor employed this component is generally indicated by the outline 53.

The pole structure of the present invention is illustrated as comprising the main poles. in the generator of the example assumed for purposes of explanation. Fig. 5 shows in side elevation one suitable type lamination 61 for the purposes of the present invention although as should appear hereinafter, the particular shape of the lamination may be altered somewhat without affecting the principles of the present invention. The lamination 61 is provided with an arcuate edge. 63 which merges into flanges 65, the arcuate edge. 63 contoured to the. rotor outline 53 (Fig. 3). The further arcuate. edge 67 of the lamination 61 opposed to the. arcuate edge 63 is provided with slots or notches 69 adapted to accommodate welds 71 and 71 (Fig. 3); which serve-to secure a plurality of the laminations 61 in closely stacked array as shown in Fig. 4. Apertures 73 are punched in the individual laminations 61 to permit the use of a compensating winding 75 (Fig. 3) provided for the conventional purpose of neutralizing the armature reaction.

Figs. 6 and 7 show a suitable retaining cup 35 adapted partially to encase the array of laminations 61, the laminations being similarly oriented such that: the. arcuate edges 63 thereof define an arcuate; surfacefacingthe rotor 53 and separated therefrom by the air gap. The cup is suitably apcrtured at 73' to accommodate the compensing winding 75 which extends through the apertures 73 of the laminations 61. In order to prevent the coolant which is circulating about the cup from gaining access to the cup interior and laminations, sleeves 77 (Fig. 3) adapted to contain the compensating winding 75 penetrate the cup. and laminations through the apertures 73 and 73. The sleeves are inserted in the apertures and then flanged (not shown) to abut the cup exterior, silver solder serving to maintain fluid tight seals between the flanges and cup.

A peripheral flan e 87 is provided on the retaining cup 85 to bear against the external circumference of the inner shell 33 (Fig. 3) being brazed thereto to provide positive location of the pole structure and insure a liquidtight connection to prevent the coolant from reaching the air gap. The upper surface (Fig. 7) of the retaining cup is contoured to the inner surface of the yoke 11. toinsure excellent magnetic contact between the yoke and the cup.

The array of laminations 61 in the retaining cup 85 is secured thereto through a construction provided to attach the pole structure to the yoke 11 beneath the bridge 19. This structure comprises one or more internally threaded thimbles 91 (Figs. 3 and 4) formed Within the apertures bored in the lamination array, such apertures opening through the top of the retaining cup 35 as is indicated by the circles 23. (Fig. 6). These apertures are bored through the central weld 71 which fills- The form the thimbles also. serves to bond the lamination.

array to the cup about the openings 95 thereby insuring a fluid impermeable cup. The main windings 1d!) are then disposed about the cup 85 between the yoke 1i and the shell 33 to comprise a completed pole structure.

What is claimed is:

1. Pole structure for dynamo-electric machines comprising in combination, a plurality of laminations, means for securing the laminations in stacked array, a unitary retaining cup partially encasing the laminations, and means for securing the laminations in the cup.

2. Pole structure for, dynamo-electric machines comprising in combination, a plurality of laminationsv each having at least one arcuate edge, means for securing the laminations in stacked array with the arcuate edges thereof defining a common arcuate surface, a unitary retaining cup encasing the laminations with the arcuate surface formed thereby exposed through the mouth of. the cup, and means for securing the laminations to the cup.

3. Pole structure for dynamo-electric machines comprising in combination, a plurality of laminations each having a pair of arcuate edges, means for securing. the laminations in closely stacked array with the arcuate edges thereof similarly oriented to define a pair of arcuate surfaces, a retaining cup tightly encasing the laminations with one of said arcuate surfaces exposed through the mouth of the cup, the array of laminations having at least one opening formed in the other of said arcuate surfaces and the cup having an aperture alined. therewith, and means disposed in said aperture and opening for securing the laminations to the cup.

4. Pole structure adapted for attachment to the yoke of a dynamo-electric machine comprising in combination, a plurality of laminations each having at least one arcuate edge, means for securing the laminations instacked array with the arcuate edge of each lamination similarly oriented to define a common arcuate surface, a retaining. cup encasing the laminations with the arcuate surface formed thereby exposed through the mouth of the cup, the portion of the cup and laminations disposed opposite the mouth and arcuate surface having at least one aperture therein, and means extending from said aperture to the yoke for securing the cup and laminations thereto with said arcuate surface directed inwardly of the yoke.

5. The pole structure of claim 4 wherein the plurality of laminations and the cup have alined openings therethrough to accommodate a compensating winding, sleeves adapted to contain the winding extending through the alined openings and secured to the cup, and wherein the means extending from said aperture to the yoke comprise at least one thimble within the aperture secured to the laminations and having internal threads and at least one screw extending from the yoke to engage the threads of the thimble.

6. Pole structure adapted for attachment to the yoke of a dynamo-electric machine comprising in combination, a plurality of laminations each having a pair of arcuate edges, means for securing the laminations in closely stacked array such that the arcuate edges thereof are similarly oriented to define a pair of arcuate surfaces, an inverted retaining cup having an arcuate top and open bottom tightly encasing the laminations, one of said arcuate surfaces being exposed through the bottom of the cup, a peripheral flange on the cup extending adjacent to the edges of said one of the arcuate surfaces, the array of laminations having at least one opening formed in the other of said arcuate surfaces and the cup having an aperture alined therewith, and means disposed in said aperture and opening for securing the laminations to the cup, and the latter to the yoke of the machine such that the arcuate top of the cup abuts the yoke.

7. Pole structure adapted for attachment to an annular yoke of a dynamo-electric machine of a type having an outer shell abutting the yoke external periphery and in apertured inner shell within the yoke and spaced from the internal periphery thereof to accommodate liquid coolant comprising in combination a plurality of laminations each having at least one arcuate edge, means for securing the laminations in stacked array with the arcuate edge of each lamination similarly oriented to define a common arcuate surface, a retaining cup encasing the laminations with the arcuate surface formed thereby exposed through the mouth of the cup, a peripheral flange on the cup extending about the mouth thereof, the portion of the cup and laminations disposed opposite the mouth and arcuate surface having at least one aperture therein, and means extending from said aperture to the yoke for securing the cup and laminations thereto with said arcuate surface penetrating the apertured inner shell and the cup flange abutting the inner shell.

8. Pole structure for dynamo-electric machines adrnitting of circulating coolant comprising a plurality of laminations each having at least one arcuate edge, means for securing the laminations in closely stacked array with the arcuate edges thereof similarly oriented to define an arcuate surface, an inverted retaining cup having an open bottom tightly encasing the laminations, said arcuate surface being exposed through the bottom of the cup, the array of laminations and the cup having a pair of alined openings therethrough to accommodate a compensating winding, a pair of sleeves adapted to contain the Winding extending respectively through the alined openings and secured to the cup to permit coolant to circulate about the cup above the open bottom thereof without access to the laminations.

References Cited in the file of this patent UNITED STATES PATENTS 922,760 Firmin May 25, 1909 941,456 Howell Nov. 30, 1909 1,319,225 Kester et al. Oct. 21, 1919 2,300,864 Baudry et al. Nov. 3, 1942 

